Fall arrester as part of a fall protection system for ladders and similar climbing routes

ABSTRACT

A catch device, as part of a fall protection for ladders and similar climbing devices, for application in a guide rail with a C-profile, includes a body and at least two pairs of rollers, arranged in the body so as to run inside the guide rail. At least one pair of rollers is rigidly fixed to the body and one roller pair is arranged to pivot about an axis at right angles to the longitudinal axis of the guide rail and which runs up to the rotational axis of the roller pair. The pivoting roller pair can be fixed in a secure position such that the pivoting roller pair is fixed on a shaft, mounted so as to rotate in the body, the upper end of the shaft projecting from the body and having an indent. A hanging latch is connected to the body which may engage in the indent. The hanging latch can be locked in the engaged position.

The invention relates to a fall arrester which forms part of a fallprotection system for ladders and similar climbing routes and can beinserted into a guide rail with a C-profile. The fall arrester has abody and two pairs of rolls which are arranged on the body so that theyrun inside the guide rail.

Such a fall arrester is known from EP 0 168 021. Both pairs of rolls arearranged swivellably about an axis which runs at right angles to thelongitudinal axis of the guide rail and to the axis of rotation of thispair of rolls. Due to the swivellable arrangement of the pair of rollsthe fall arrester can be inserted into the guide rail at any point. Forinsertion the pairs of rolls are swivelled so that the axis of rotationof the rolls points in the longitudinal direction of the rail. Afterinsertion of the fall arrester into the guide rail the pairs of rollsare then swivelled into their normal or secure position and secured inthis position.

A fall arrester is known from DE 27 36 037 in which the parts which griparound one guide flange of the guide rail are swivellable about an axiswhich runs parallel to the guide rail. These parts can thereby be movedin the direction of the parts of the fall arrester gripping around theother guide flange, whereby the fall arrester can then be removed fromthe guide rail. To lock the fall arrester in the secure position athreaded bolt is tightened by means of a box spanner or an additionallocking pin is provided.

The object of the invention is to simplify the design of the fallarrester and at the same time to increase the operational safety.

According to the invention this object is achieved in that one pair ofrolls is arranged rigid against the body and the other pair of rolls isarranged swivellable about an axis which runs at right angles to thelongitudinal axis of the guide rail and to the axis of rotation of thispair of rolls.

By having one pair or rolls arranged rigid, a possible source of errorsis excluded and the design is simplified at the same time.

The swivellable pair of rolls can preferably be fixed in the secureposition. The fixing can take place in that the swivellable pair ofrolls is attached to a shank housed rotatable in the body and the end ofthe shank projects from the body and has a diametral indent.

Articulated to the body is a lever which can be inserted into the indentand locked in this position by a stop bolt.

The lever which can be inserted into the indent is preferably one leg ofa U-shaped suspended ratchet. The suspended ratchet is preferablyarticulated to the body at the base of its U-shape. On the free leg ofthe U-shape, an eyelet is provided for securing the safety belt of thepersonal safety equipment. If the fall arrester engages in the guiderail in the event of a fall, the U-shape of the suspended ratchet isbent upwards, whereby the catching impact is additionally attenuated.

Above the rigid pair of rolls a third pair of rolls is preferablyarranged, which is also rigid. This pair of rolls runs on the outside ofthe guide rail so that the two guide flanges which delimit the openingof the C-profile lie between the two rigid pairs of rolls. A largelyfrictionless movement of the fall arrester in the guide rail is therebyachieved.

The two rigid pairs of rolls are usually arranged at the front end ofthe fall arrester, while the swivellable pair of rolls are arrangedapproximately in the middle of the fall arrester. The rear end is formedas a catching pawl, which is integral with the body. The axis ofrotation of the swivellable pair of rolls is loaded towards the body bya compression spring so that, in the normal case, and during forwardmovement, the catching pawl is pushed towards the catching stop which isformed in the back of the guide rail. In the event of a fall, if thefall arrester is pulled backwards, the catching pawl impacts against thecatching stop and the fall arrester is thereby locked in the guide rail.

The catching pawl can also be formed in the body as a movable elementunder spring tension, the swivellable pair of rolls expediently beingarranged at the rear end of the body, while the catching pawl is thenarticulated in the middle of the body.

To insert the fall arrester into the guide rail, the fall arrester isfirst held at right angles to the guide rail and inserted with thefront, lower, rigid pair of rolls into the opening of the C-profile ofthe guide rail. The fall arrester is then with its rear end swivelleddown by 90° C., so that the swivellable pair of rolls and the catchingpawl can also be inserted into the opening of the C-profile. Theswivellable pair of rolls is located in its inserted position, in whichthe axis of rotation of the pair of rolls points in the longitudinaldirection of the guide rail. After the insertion of the swivellable pairof rolls and the catching pawl into the opening of the guide rail theswivellable pair of rolls is swivelled by 90° C., so that it now liesacross in the guide rail. In this position it is locked in the manneralready mentioned above.

The guide rail is generally vertical. In order to prevent the fallarrester from being inserted upside down, with the front end pointingdownwards, a device is provided which in this case prevents theswivelling of the swivellable pair of rolls into the secure position andthe swinging shut of the suspended ratchet. This device consists of twoopposed longitudinal grooves, facing the rolls, milled in the shank ofthe swivellable pair of rolls. In the inserted position one of the twolongitudinal grooves points towards the rear end of the fall arrester.From the bore in which the shank of the swivellable pair of rolls ishoused, a longitudinal bore a few millimetres thick leads to the rearend of the fall arrester. A cylindrical pin loosely slides in thislongitudinal bore. If the fall arrester is inserted upside down, i.e.head first, the cylindrical pin drops through the action of gravity intothe longitudinal groove of the shank and thereby locks the shank againstrotation.

The body of the fall arrester is expediently made from aluminium orstainless steel. The suspended ratchet, which must bend upwards in theevent of a fall, expediently consists of steel with a tensile strengthof 480 to 600 N/mm².

An embodiment of the invention is explained below with reference to thedrawings. These show:

FIG. 1 a perspective representation of the fall arrester inserted into aguide rail, part being broken away;

FIG. 2 the fall arrester inserted into a guide rail in section;

FIG. 3 a representation similar to that of FIG. 2, the suspended ratchetbeing open;

FIG. 4 a representation similar to that of FIG. 2, but with the fallarrester inserted head first and

FIGS. 5 to 8 in four steps the insertion of the fall arrester into theguide rail.

According to FIGS. 1 and 2 the fall arrester 10 is guided in a guiderail 12. The guide rail 12 is normally vertical. It has a C-profile opento the front, i.e. towards the user, the opening being laterallydelimited by two guide flanges 14. In the back of the guide railcatching stops 16 are pressed out, protruding into the guide rail 12.

The fall arrester 10 has a body 20, oblong overall, extending in thedirection of the guide rail with a catching pawl 18. At the front end ofthe body 20, two pairs of rolls 22, 24 are provided. The inner pair ofrolls 22 run on the inside of the guide flange 14, while the outer pairof rolls 24 run on the outside of the guide flange 14. The rolls 22, 24are housed on journals which are attached rigidly to the body 20. Theinner rolls 22 are at a distance from the outer rolls 24, which issomewhat greater than the material thickness of the guide flange 14.

Housed rotatable in a bore 26 of the body 20 is a shank 28, the axis ofrotation lying approximately perpendicular to the front of the guiderail 12. At the end of the shank 28 projecting towards the guide rail12, a rear pair of rolls 30 with an axis of rotation lying across theshank axis is arranged. By rotating the shank 28, the axis of rotationof the pair of rolls 30 can be swivelled parallel to the longitudinaldirection of the guide rail 12, the pair of rolls 30 then being locatedin the inserted position. The pair of rolls 30 can also be swivelledacross the guide rail 12, so that its axis of rotation lies parallel tothe axes of rotation of the inner and outer rolls 22, 24. The pair ofrolls 30 is then in the secure position. The end of the shank 28projecting on the upper side of the body 20 has a transverse indent 32.On the upper side of the body 20 a suspended ratchet 34 is alsoarticulated to the rear end of the body 20. The suspended ratchet 34 isU-shaped, its centre of rotation lying in the region of the bend of theU-shape. The lower leg 36, lying closer to the body 20, lies in a milledrecess in the upper side of the body 20. The upper leg 38 is longer thanthe lower leg 36 and extends beyond the shank 28. At its front end aneyelet 40 is provided for securing the safety belt of the user'spersonal safety equipment. If the swivellable pair of rolls 30 is in thesecure position, the indent 32 points in the longitudinal direction andthe upper leg 38 of the suspended ratchet 34 can be inserted into thisindent 32. The shank 28 and the swivellable pair of rolls 30 are thuslocked against swivelling. The suspended ratchet 34 is secured in thisshut position by a stop bolt 42. The stop bolt 42 is attached laterallyagainst the body 20 and pierces the lower leg 36 of the suspendedratchet 34. The stop bolt 42 slopes at its front end so that it ispushed out when the suspended ratchet 34 swings shut and then engages ina bore 44 provided for this purpose at the front end of the lower leg36.

A catching pawl 18 is formed at the rear end of the body 20 integralwith the latter. It slopes rearward, so that upon a forward movement ofthe fall arrester it travels over the catching stops 16 sloping in thesame direction. In the event of a fall the catching pawl would movebackwards, so that the catching pawl 18 then strikes the catching stop16, and thereby locks the fall arrester 10 in the guide rail 12.

In order to ensure that the fall arrester 10 acts as a catch in theevent of a fall, the fall arrester 10 must be inserted into the guiderail 12 correctly aligned. As usual, for this a pin 50 projectslaterally to the right from the body 20 of the fall arrester. On theopposite side, i.e. on the left in the present case, of the guide rail acorresponding stop is provided, which the pin 50 strikes if the fallarrester 10 is incorrectly inserted into the guide rail 12. This stop isusually provided only at the upper and lower ends of the guide rail, asthe fall arrester is customarily inserted only at these points. As thefall arrester 10 according to the invention can be inserted at any pointof the guide rail 12, an additional device is provided which warns theuser of incorrect insertion of the fall arrester 10. This deviceconsists of a cylindrical pin 52 and two longitudinal grooves 54 whichare cut into the cylinder surfaces of the shank 28 at opposite points.The cylindrical pin 52 slides freely in a bore 56 which extends from thebore 26 for the shank 28 to the rear end of the body 20. The rearopening of the longitudinal bore 56 is sealed by a grub screw 57 (FIG.3). If the fall arrester 10 is inserted wrongly aligned into the guiderail 12, the cylindrical pin 52 drops under its own weight into one ofthe longitudinal grooves 54, thereby blocking swivelling of the pair ofrolls 30 (FIG. 4). The longitudinal grooves 54 are attached to the sidesfacing the rolls 30, so that the pair of rolls 30 cannot then beswivelled into the secure position and the suspended ratchet 34 cannotbe swung shut. The user is thereby warned of an incorrect alignment ofthe fall arrester.

A nose 58 projects from the front end of the lower leg 36 of thesuspended ratchet 34, engaging in an indent 60 at the upper end of theshank 28 if the swivellable pair of rolls 30 is in the secure position.In the event of a fall the U-shape of the suspended ratchet 34 is bentupwards, the catching impact thereby being attenuated. The upper leg 38is pulled out of the indent 32 in the process. The engagement of thenose 58 in the indent 60, ensures that the swivellable pair of rolls 30remains in the secure position even if the upper leg 38 is pulled out ofthe indent 32.

The bore 26 has a shoulder 62 and is widened in the upper section. Theshank 28 has a corresponding counter-shoulder 64 and a widened head 66,in which the indent 32 is provided. A compression spring 68 is supportedbetween the shoulder 62 and counter-shoulder 64. The swivellable pair ofrolls 30 are therefore pulled towards the inside of the guide flange 14,whereby the catching pawl 18 is pushed towards the back of the guiderail 12 and thus towards the catching stops 16. It is thereby guaranteedthat in the event of a fall the fall arrester will be safely caught inthe guide rail 12.

The insertion of the fall arrester 10 is now explained with reference toFIGS. 5-8:

As shown in FIG. 5, the fall arrester 10 is held across the guide rail12 and the inner, rigid rolls 22 are inserted through the opening of theC-profile of the guide rail 12 in the process. The suspended ratchet 34is swung open and the swivellable pair of rolls 30 swivelled into theinserted position, in which the axis of rotation of the rolls 30 pointsin the longitudinal direction of the fall arrester 10.

The fall arrester 10 is then swivelled into the position shown in FIG.6, care needing to be taken that the guide flange 14 comes to restbetween the inner rolls 22 and the outer rolls 24 in the process. Therear end of the fall arrester 10 is further raised somewhat from theguide rail 12. In order to make this raised position possible, the innerrolls 22 are offset slightly forwards vis-à-vis the outer rolls 24. Thefall arrester 10 is then swivelled with its rear end towards the guiderail 12, so that the swivellable pair of rolls 30 and the catching pawl18 are now also inserted through the opening of the C-profile into theguide rail 12, as shown in FIG. 7.

The shank 28 and thus the pair of rolls 30 are then swivelled by 90°, sothat the pair of rolls 30 are transversely aligned and lie parallel tothe rolls 22, 24. Finally the suspended ratchet 34 swings shut, theupper leg 38 coming to rest in the indent 32 in the head of the shank28. On the swinging shut of the suspended a ratchet 34, the stop bolt 42engages in the bore 44 on the lower leg 36 of the suspended ratchet 34,see FIG. 8. The fall arrester 10 is then ready for use.

LIST OF REFERENCES

-   10 Fall arrester-   12 Guide rail-   14 Guide flange-   16 Catching stops-   18 Catch-   20 Body-   22 Inner rolls-   24 Outer rolls-   26 Bore-   28 Shank-   30 Pair of rolls-   32 Indent-   34 Suspended ratchet-   36 Lower leg-   38 Upper leg-   40 Eyelet-   42 Stop bolt-   44 Bore-   50 Pin-   52 Cylindrical pin-   54 Longitudinal grooves-   56 Longitudinal bore-   57 Grub screw-   58 Nose-   60 Indent-   62 Shoulder-   64 Counter-shoulder-   66 Head-   68 Spring

1. (canceled)
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 5. (canceled) 6.(canceled)
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 8. (canceled)
 9. (canceled)
 10. (canceled) 11.A fall arrester which forms part of a fall protection system for laddersand similar climbing routes and can be inserted into a guide rail with aC-profile, the guide rail defining a longitudinal axis, the fallarrester comprising: a body defining a front end and a rear end of thefall arrester and at least a first and a second pair of rolls which arearranged on the body and are adapted to run inside the guide rail, therolls having an axis of rotation; wherein the first pair of rolls isarranged rigid against the body and the second pair of rolls is arrangedswivellable about an axis which runs at right angles to the longitudinalaxis of the guide rail and to the axis of rotation of this pair ofrolls.
 12. The fall arrester of claim 11, wherein the swivellable pairof rolls is adapted to be fixed in a secure position.
 13. The fallarrester of claim 12, wherein the swivellable pair of rolls is attachedto a shank housed rotatably in the body, the upper end of the shankprojects from the body and has an indent and a suspended ratchet isarticulated to the body and is adapted to be inserted into the indent.14. The fall arrester of claim 13, wherein the suspended ratchet isadapted to be locked in the inserting position.
 15. The fall arrester ofclaim 14, wherein the suspended ratchet is U-shaped and has an upper andlower leg and a bend therebetween.
 16. The fall arrester of claim 15,wherein the suspended ratchet is articulated at the bend of its U-shapeto the body, an eyelet is provided on the upper leg for securing asafety belt of personal safety equipment and the lower leg is able to belocked against the body.
 17. The fall arrester of claim 16, whereinarranged above the rigid, first pair of rolls is a further pair ofrolls, which is also rigid, and the arrangement is such that one rigidpair of rolls runs on the inside of the guide rail and the other rigidpair of rolls on the outside.
 18. The fall arrester of claim 11, whereinthe rigid pair of rolls is arranged at the front end of the fallarrester, while the swivellable pair of rolls is arranged approximatelyin the middle of the fall arrester and the rear end of the body isformed as a catching pawl.
 19. The fall arrester of claim 18, whereinthe swivellable pair of rolls is loaded towards the body by a spring, sothat the catching pawl is pushed towards a catching stop formed in theguide rail.
 20. The fall arrester of claim 13, wherein two oppositelongitudinal grooves are milled in the shank of the swivellable pair ofrolls, the opposite longitudinal grooves facing the swivellable pair ofrolls, wherein a longitudinal bore leads from a bore in which the shankof the swivellable pair of rolls is housed to the rear end of the fallarrester, wherein in the longitudinal bore a cylindrical pin looselyslides, which is adapted to drop under the action of gravity into one ofthe longitudinal grooves of the shank and, thereby, to lock the shankagainst rotation, in the event of the fall arrester being insertedincorrectly.